Intermediate bucket and support for turbines.



No. 792,659. I PATENTED JUNE 20, 19-95.

O.JUNGGREN. INTERMEDIATE BUCKET AND SUPPORT FOR TURBINES.

PPPPPPPPPPPPPPPPP 3318,1904.

Witm eeee s: nvenbor Oscar unggren,

NITED STATES latentecl June 20, 1905.

PATENT OFFICE.

OSCAR J UNGGREN, OF SCHENEOTADY, NEW YORK, ASSIGNOR TO GEL ERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

INTERMEDIATE BUCKET AND SUPPORT FOR TURBINES.

SPECIFICATION forming part of Letters Patent No. 792,659, dated June 20,1905.

Application filed February 18, 1904. Serial No. 194,204.

To all iii/1,0712 [/7 iii/my concern:

Be it known that I, OSCAR J UNGGREN, a citizen of the United States,residing at Schenectady, county of Schenectady, State of New York, haveinvented certain new and useful Improvements in Intermediate Buckets andTheir Supports for Elastic-Fluid Turbines, of which the following is aspecification.

The present invention relates to intermediate turbine-buckets which aresituated between the rows of wheel-buckets and are employed to reversethe direction of the fluid stream or streams and discharge it or them atthe proper angle against the adjacent row of wheel-buckets. Theintermediate buckets are stationary and are separated from thewheelbuckets or some part of the wheel by a very small clearance, whichclearance to a very great degree affects the economy of the machine. Thesmaller it is the greater will be the economy, because the leakage ofthe motive fluid is correspondingly reduced. The clearance is frequentlyas low as .02 of an inch and varies from that to .05 of an inch. Inorder to efliciently transform the energy of the motive fluid intouseful work, it is necessary to have a relatively high bucket speed, andit is common practice to operate turbines with a bucket speed of fourmiles per minute and above. Owing to the high peripheral speed of thewheel and to the distortion of the parts due to unequal expansion, thesupport for the intermediates becomes an important consideration becauseof the liability of injury due to contacting of the relatively movableparts. Another thing to be taken into account is the expansion in aradial direction of the working passage between the buckets.

Prior to my invention it was the practice to cut the intermediate on theconvex side of a segmental piece of stock by means of a bucketcuttingmachine, it being the only way that buckets can be cut on the machineswith which I am familiar. This meant'that in order to get the desiredgradual expansion of the passage it was necessary .to bevel the outerends of the buckets, which engage with a fixed support carried by thecasing. Bolts for securing the parts in place were arranged to extendthrough the segment on which the buckets were formed andalso through thebuckets themselves into the support. tion is open to the seriousobjection that when the securing-bolts are tightened they have atendency to cause the intermediates to shift bodily in the direction ofthe bevel on theends of the buckets. Any clearance what- This construc'ever around the body of the bolt such as is through long thin bucketshaving a tapered end. When the intermediates extend around or largelyaround the wheel and are made in several sections, the difficulty ofadjusting all of the sections exactly right is apparent.

My invention has for its object to improve and simplify the constructionof intermediate buckets and their support, whereby the cost is reducedand the buckets may be quickly and accurately set.

In carrying out my invention I cast the buckets integral with asegmental base or support located at their outer ends, the inner endsadjacent to the wheel being disconnected. Some or all of the buckets areprovided with integral tenons by which a thin cover forming one part ofthe bucket-spaces is attached. The segmental support is beveled betweenbuckets to give the necessary enlargement toward the exhaust, the thincover being straight, or substantially so. The periphery of thesegmental support is finished in any suitable manner and is seated in aclosefitting groove in the wheel casing or support. Bolts of substantialsize are arranged to pass through the casing and secure the parts inplace.

One of the distinguishing features of my invention is that the segmentalbase-piece on which the buckets are formed is located at the point ofgreatest diameter, whereas with the old construction it was located atthe point of least diameter.

In the accompanying drawings, which illustrate one embodiment of myinvention, Figure 1 is a detail sectional view of a set of segmentalbuckets. Fig. 2 is a sectional view taken at right angles to that shownin Fig. 1; and Fig. 3 is a longitudinal section of an intermediatebucket, illustrating the old construction.

Referring to Fig. 3, 1 represents the segmental base-piece adjacent tothe-wheel and having buckets 2 formed integrally therewith. Thesebuckets are cut from the solid stock by a suitable bucket-cuttingmachine and radiate from acommon center. The outer ends of the bucketsare beveled, as indicated at 3, and these beveled ends engage with thecorrespondingly-beveled surfaces on the support 4. The buckets andsupport are drilled to receive the retaining-bolts 5, which radiateoutwardly from a common center. In other words, the head of the bolt islocated adjacent to the wheel and the nut at a point adjacent to thewheel-inclosing casing. When the nut is tightened, it has a tendency tomove the buckets bodily to the right, owing to the inclination of thesurface 3. ,There is always some space around the body of the bolt whichis sufficient to throw the buckets out of their proper alinement.

In Figs. 1 and 2 is shown a construction by means of which I obviate theobjections referred to in connection with the old style of bucket shownin Fig. 3. This represents a plurality of radial or substantially radialbuckets 6, which are cast integral with a basepiece 7, which ispreferably although not necessarily made up in segments. This dependslargely on whether the buckets are to cover a small or great angularportion of the wheel. The base portion is formed at the outer ends ofthe buckets where the diameter is greatgle thereto if it be desired tochange the cross-sectional area of the bucket-spaces. In order tocompensate for the increased volume of the motive fluid, it is necessaryto expand the bucket-spaces in the direction of the exhaust. It ispreferable to make this expansion gradual, and in the present instance Iobtain this expansion by beveling or cutting away the space between theadjacent buckets, as indicated at 11. It is to be noted that the beveledsurface extends from one side of the bucket to the other, which insuresa gradual expansion of the cross-sectional area of the passage. Theperiphery of the base-piece 7 is finished in any suitable manner inorder that it may be securely mounted in the wheel-casing 12 or othersupport. In the present instance the base-piece is provided with asmooth peripheral surface and side walls 18, which are parallel witheach other and extend at right angles to the peripheral surface. Thewalls 13 are arranged to engage with the side walls of a groove formedin the support or casing 12. The base-piece is tapped at a number ofpoints to receive the retaining-bolts 1 1, the latter being ofsubstantial size and accessible from the outside of the casing. Betweenthe head and the body of each bolt is a tapered portion 15, whichengages with a conical seat formed on the support or casing 12 and whichprevents the escape of any steam or other motive fluid around the bodyof the bolt.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is

1. In an elastic-fluid turbine, the combination of a casing, a pluralityof radial or substantially radial buckets, a base which is formedintegral with the buckets and located at the point of greatest diameter,the said buckets being unconnected at their inner ends, means forsecuring the base which are accessible outside of the casing, a coverfor the buckets which is located at the point of least diameter, andmeans for mounting the base in place.

2. In an elastic-fluid turbine, the combination of a grooved casing orsupport, a segmental base-piece having a finished periphery which fitsinto the groove, integral buckets which extend inwardly toward a commonpoint of lesser diameter, and cut-away portions which increase thecross-sectional area of the spaces between buckets, a cover for theinner ends of the buckets, and bolts for retaining the buckets in place,which pass through the support into the segmental base-piece.

3. As an article of manufacture, an intermediate for an elastic-fluidturbine, comprising a base-piece, buckets formed integral with the baseat their outer ends or point of greatest diameter, and having separateinner ends, the working passages between the buckets eX- ITO pandingtoward the exhaust, a separable cover for the inner ends of the buckets,which is curved on a smaller radius than the base-piece, and meanspassing through holes in the cover for securing it in place.

4. As an article of manufacture, an intermediate for an elastic-fluidturbine, comprising a segmental base having a finished outer surface forengagement with a support, and

I0 cut-away portions to increase the area of the bucket-spaces, aplurality of integral buckets extending inwardly toward a point oflesser diameter, and a sheet-metal cover which is attached to the innerends of the buckets.

In witness whereof I have hereunto set my 5

